1. Field of the Invention
The present invention is related generally to jigs for the placement and guidance of mortising tools. More specifically, it is directed to a self-contained jig which enables adjustable positioning and sizing of a mortise and which enables use of a router to form finish or shallow mortises for mounting of hardware, such as flush bolts, hinges, strike plates, reinforcement plates, finish lock mortises in door edges, and other hardware which can be advantageously flush mounted.
2. Description of the Related Art
Mechanical devices of many types, such as hinges, reinforcement plates, and the like, often require a shallow mortise to be made in a surface so as to enable the device to be flush mounted in the surface. Typical of such devices are various lock assemblies which may require initial deep or rough boring of surfaces as well as shallow or finish mortising for parts of the lock assemblies.
Locks for doors are generally either tubular or cylindrical locks, both types requiring the boring of holes in the edge and face of the door and in the jamb of the door frame to receive the bolt and latch assemblies. Tools for making these rough bores are known in the art, as are tools designed to guide boring tools.
The rough bore tools do not, however, enable the placement of the lock assembly face plate or strike plate such that the plates are flush with the surface in which the plates are installed. Flush placement is desirable for correct and smooth operation of the door and lock. When boring tools known in the art are used to make the rough bore for a lock, the locksmith must then provide a shallow or finish mortise to achieve the flush mounting of the plates. This is almost invariably done by using a hammer and chisel to create the shallow mortise. This has always been difficult to do precisely and a mistake could ruin the entire door, preventing correct installation of the lock and operation of the door. Moreover, the correct preparation of a quality finish mortise is very tedious and time consuming and is the most visible criterion by which the craft of the locksmith or installer is judged.
Another difficulty encountered in the art results from the variety of materials used for doors and particularly for door edges. These materials include wood (of various hardnesses), vinyl, sheet metal, aluminum, compressed paper products and structural foam under a vinyl layer. With many such materials, the use of a hammer and chisel to create the finished mortise may be made more difficult or may even be precluded.
Yet another problem not solved by devices in the art is the need for the finish mortise to compensate for the bevel in some door edges. That is, some door edges are slanted from one door face to the other so that the width of the face of the door whose edge first contacts the door jamb when the door is closed is slightly less than the width of the opposite door face. This enables the door to close properly with a reduced margin between the door edge and the frame of the door. Creating a mortise for such a door edge that enables the face plate to be flush mounted is not possible using tools and techniques known in the art.
Although the precise placement of the rough bores for locks and other hardware is usually not very important, precision placement for finish mortising is extremely important. Moreover, different plates to be flush mounted may require different widths and lengths of finish mortises. Tools and techniques known in the art lack simple adjustable means for quickly, easily and precisely positioning a template for making the mortise, and the art also lacks a jig having means for quickly, easily and precisely adjusting the width and length of the finish mortise.
Mortising tools in the art typically use several removable blocks inserted between the tool body and the door faces to adjust the position of the tool. The need to handle and simultaneously place several blocks in different positions is extremely awkward and time consuming. Moreover, such tools do not enable position adjustment over a continuous range, but rather only in discrete, predetermined amounts. Another disadvantage of such tools is that the user is forced to carry a variety of sizes of the blocks to accommodate different size doors, adding to the inconvenience of using the tools.
Other mortising tools in the art employ several threaded turnscrews, usually at least one at each extremity on each side of the tool, to adjust the position of the tool on the door. Such tools are difficult to adjust and require several independent adjustments and, usually, readjustments, to ensure that each part of the mortising tool is the same distance from the door surface. An important disadvantage of such tools is that it is virtually impossible to set each and every turnscrew to match the setting of every other screw, and thus the quality and the appearance of the resulting mortise may suffer.
Related tools in the art accomplish a very limited provision for different mortise sizes, typically by requiring the use of a separate template part to be inserted in a standard size jig aperture. A different template part must be used for each different size mortise. The disadvantages of such systems include multiplicity of parts to be carried by the installer, excessive time consumption in the identification of the appropriate template part and in its installation into the jig aperture, lack of a continuous range of mortise sizes to enable custom mortising, and complexity of use. The inconvenience and expense of such systems is well known to practitioners of the art.